American Goldeneye: (Bucephala clangula)

Among Goldeneyes pair formation begins in midwinter, and until then the two sexes often form separate flocks. Indeed, male Common Goldeneyes winter farther north than do the females. Goldeneyes can dive to depths of 20 feet (6 meters) or more, but generally limit themselves to about 10 feet (3 meters). Their preferred winter foods are mollusks and mud crabs; the crop of one bird on the Pacific Coast contained the remains of 26 mud crabs.